Threading web material



C. ALLANDER ETAL THREADING WEB MATERIAL 2 Sheets-Sheet 1 INVENTORSICLAES ALLANDER BENGT LANNE svEN wALLlN BY ATTYS.

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April 16, 11963 Filed Aug. 26, 1959 April 16, 1963 3,085,346

c. ALLANDER ETAL Filed'Aug. 26 1959 THREADING WEB MATERIAL 2Sheets-Sheet 2 INVENTOR SI CLAES ALLANDER BENGT LANNE SVEN WALLIN ATTYS.

United States Patent O THREADHNG WEB MATERIAL Claes Allander, ScdraAngby, and Bengt Laune and Sven Wallin, lonkoping, Sweden, assignors toAktiebolaget Svenska Flalrtt'ahriken, Stockholm, Sweden Filed Ang. 26,1959, Ser. No. 836,221 Claims priority, application Sweden Dec. 4, 19535 Claims. (Ci. 342-46) The present invention. relates to a method andapparatus for threading, i.e. guiding and transporting the leading endof a web, particularly a web of wet material with low mechanicalstrength, which is to be transported air-borne in one or more runsthrough a drier or similar apparatus by means of a treating medium beingblown against the web.

In all treatment of web materials in apparatus of the above mentionedtype it has always been a diicult problem to guide and transport theleading end of the web. It has previously been customary at the turningpoints of the web between the different runs to manually transfer theleading end of the web between the transport elements of the differentpassages. Besides being time-consuming this manual procedure isespecially ditlicult to carry out when treating a wet material with lowmechanical strength, for instance cellulose pulp. The lower transportspeed necessary in the manual threading procedure .when treatingcellulose pulp also requires a certain complicated adjustment in thepreceding Iwet section of the treatment apparatus. Even greaterdiiiculties for the threading exist in the driers developed in recenttimes which are made without conveyors and where the web is carriedcompletely air-borne, since it is necessary to forcefully guide theleading end of the web continuously along its entire path oftransportation and thus not only at its turning points. For conservingspace the runs of the web must be arranged at such a relative distancethat a manual forceful guiding of the leading end of the web between theturning points is quite impossible. Furthermore, devices are known whichprovide an automatic threading by inserting the leading end of the webbetween' two endless conveyors running along one side of the web, whichconveyors carry the web through the drier. In larger driers, where theweb is carried in a large number of runs through the apparatus, however,such an arrangement is too complicated and costly.

The present invention which relates to a new method and apparatus forthreading without using mechanical transporting means is characterizedin that the leading end of the web is kept stretched in the transportdirection of the web and is prevented from fluttering by being connectedwith a threader having an air-borne or floating pilot inserted in,advance of the web in the `apparatus the pilot being made of lightmaterial having a great area relative to weight and having asubstantially plain surface for supporting and transporting the pilot bythe aid of the upward and forward directed power components respectivelyof said treating medium.

The pilot used may either be attached directly to the leading end of theweb or by means of one or several ropes or bands. When carrying out thenew method it is advisable that the web in a known way be torn or cutolf at its leading end from one edge of the web diagonally across theweb to its opposite edge, so that a long and narrow ap is formed and thepilot connected with the mentioned flap. In carrying out the method, apilot consisting of a dried piece of the web may suitably be used or thepilot may consist of a Substantially plain sheet of another materialwith suitable connecting means for the connection of the pilot with theleading end of the web. The pilot or the threader may also in accordancewith a suitable method be made of two layers of material "ice in theform of a backwards open sack, which may be divided by longitudinalseams into several units.

The invention also relates to an apparatus for the performance of themethod. Such an apparatus is characterized in that the connecting meansconsist of an angular double folded band, the Shanks of which -by inlaidsprings are kept pressed against each other and a relatively long rope,or other similar connecting means attached between the band and thepilot, which rope before the threading is kept coiled in a readyposition in front of the apparatus in a revolvable magazine. A guiding:means or trumpets is directed diagonally towards the straight edge ofthe leading end of the web and is furnished with an inlaid angular bar,which by the insertion of the band opens the Shanks and keeps them openuntil they pass the end of the enclosed bar, where said bar encloses theedge of the web at this point they are released and grip around the edgeof said web, whereby the leading part of the web thereafter is keptstretched by the threader and is carried through the apparatus.

The invention will now be described more -fully with suitable referenceto the accompanying drawings, which show one form of an apparatus forperforming the method, in which:

FIG. 1 shows a longitudinal section of a drier furnished with athreading apparatus according to the invention.

FIG. 2 is a plan View of a part of the threading apparatus;

FIGS. 3 to 5 inclusive are details in fragmentary perspective of adouble folded band used for connecting the pilot to the web;

FIG. 6 is a perspeitive View of the guiding means or trumpet forengaging the threader with the web;

FIG. 7 is a perspective View of the pilot of the threader;

FIG. 8 is a perspective view of a modified spring detail of theconnecting means; and

FIG. 9 is a perspective view of a modied pilot.

In the drawings a web-like material 1, `after having passed a pair ofrolls 2 which constitute the last part of a forming and pressingsection, is brought through an opening 3a into a drier 3 or othertreating apparatus, where the web-like material is transported forwardin one or more runs 4a, 4b etc. over a number of rolls 5a, 5b etc.indicates an outlet opening for the treated web-like material. Thethreader for the drier 3 has a pilot 6 made with a substantially plainsurface for supporting and transporting the pilot with the -aid of theupwardly and forwardly directed power components of the treating mediumbeing supplied -for drying the web. In the embodiment shown in FIGS. 1to 7 the pilot 6 consists of a piece of an already dried web. As shownin FIG. 9, the pilot 6a may also be made of two layers 21 and 22 ofmaterial in the form of a backwardly open sack, which by longitudinalseams 23 is divided into several straight or tapered units. A rope 7 isattached at the rear end of the pilot 6 or 6a, the other end of saidrope being connected with the leading end of the web 1, which in thecase shown is shaped as a long and narrow flap la, formed in a known wayby tearing ot the leading end of the web from one edge of the webdiagonally across the web over to its opposite edge. The rope 7 isattached to the web by an angular double-folded band 8 (see FIGS. 3 and4), the shanks 8a and 8b of which are pressed against each other bymeans of inlaid springs 9. The spring means 9 may consist of triangularelements 18a and 18h (see FIG, 5) inlaid in the Shanks 8a and 8b, or mayconstitute rectangular elements '19a and 1911 (see FIG. 8) inlaid in theshanks 8a and 8b. This band before the threading is kept coiled in aready position in a revolvable magazine lll, placed in front of thedrier 3. A stationary plain table 151 supports aossas the web during thethreading. In the illustrated ernbodiment, the table is constructed likea box with perforated top wall 24 for supplying a gaseous medium toreduce the friction between the wet web and the table 11. At one side ofthe table 11 a guiding means or trumpet 12 for the band 8 is directeddiagonally towards the straight edge 1b of the flap of the web and isfurnished with an inlaid angular rail 13y (see FIGS. 2 and 6), whichrail during the insertion of the band at the end 13b engages between theshanks 8a and 8b of the band to open them, the central portion of therail 13 keeping the Shanks open until they, at the end l13m of theinlaid rail where said rail embraces the edge 1b of the web, arereleased and grip around the straight edge 11b of the web. The liap ofthe material will in this way be stretched by the pilot andautomatically will be transported through the drier. The invention isespecially intended for driers with an airborne web, but is of coursealso applicable to driers provided with mechanical conveyors fortransporting and supporting the web.

What we claim is:

1. A method for threadingy through a treating apparatus the leading endof a sheet of wet web material with low tensile strength, wherein theweb material is transported air-borne in at least one run by means of atreating medium impinged `against the web in an upward and forwarddirection, comprising the steps of providing a light-weight pilot sheetof greater tensile strength than said web and having a substantiallyplain surface of sufficient area relative to weight as to also beair-borne and A.

moved forward by said treating-medium, providing on said pilot afoldable band extending rearwardly from one side of said pilot,connecting said pilot to the leading end of the web material by foldingsaid band over one edge of the web material, inserting said pilot intothe treating apparatus in advance of the web material, and supportingand transporting said pilot through the drier by the upwardly andforwardly directed components of the treating medium to support thepilot and stretch the forward end of the sheet of web materaial in thedirection of travel through the apparatus to prevent fluttering andtearing of the forward end of the wet web material of low tensilestrength, the pilot and the web material sheet being transportedtogether air-borne by the treating medium with the pilot sheetentraining the forward end of the web sheet. f

2. A device for threading the leading end of a sheet of web material oflow tensile strength through a treating apparatus having guiding rollsproviding horizontal runs therebetween and means forming jets oftreating medium underlying said runs to impinge against the underside ofthe web in an upward and forward direction to move the web forwardair-borne along said runs, said device comprising a pilot of a materialhaving greater strength than said web material and having a body ofsheet form with a plain lower surface of sufficient area relative toweight as also to be floatingly supported and moved forward by theupwardly and forwardly directed components of the impinging jets of saidtreating medium, and means connecting said pilot with the leading end ofthe web, said pilot being formed of two superposed sheetsheld togetherby at least two longitudinal seams forming i at least one sack-likespace opening to the rear of the pilot.

3. A device for threading the leading end of a sheet of web material oflow `tensile strength through a treating apparatus having guiding rollsproviding horizontal runs therebetween and means forming jets oftreating medium underlying said runs to impinge against the underside ofthe web in an upward and forward direction to move the web forwardair-'borne along said runs, said deviee cornprising a pilot of amaterial having greater strength than said web material and having abody of sheet lform with a plain -lower surf-ace of suiiicient arearelative to weight as also to be -floatingly supported and moved forwardby the Iupwardly and forwardly directed components of the impinging jetsof said treating medium, and means connecting said pilot with theleading end of the web, said pilot including a band extending rearwardlyfrom the body thereof, and edge-engaging clip means carried by said bandfor fastening the same to the side edge behind Y paratus having guidingrolls providing horizontal runs therebetween and means forming jets oftreating medium underlying said runs to impinge against the underside ofthe web in an upward and `forward direction to move the web forwardair-borne along said runs, said device comprising la pilot of a materialhaving greater strength than said web material and having a -body ofsheet for-m with a plain lower `surface of sufficient area relative toweight Ias also to be lioatingly ysupported and moved forward by theupwardly and forwardly directed components of the impinging jets of saidtreating medium, and means conneeting said pilot with lthe leading endof the web, said sheet of web material being formed to have a taperedleading edge extending from one side edge thereof, and `connecting meansincluding a relatively long ropelike element extending rearwardly fromsaid pilot and terminating rearwardly in a double-folded angular bandhaving spring means Itherein operable to press the shank-s of Ithe bandtoward each other to form an elongatedjaw-like member adapted to graspone edge of the long side of the flap of the web.

5. Apparatus as set forth in claim 4 which fur-ther iucludes arevolvable magazine adjacent the -feed end of said treating apparatus,said band in operative position being coiledin said magazine, and guidemeans including Y an angular rail formed to open the Shanks of thedoublefolded band and position them to grasp the edge of the flap of-the -web upon advance of the latter into the treating apparatus.

References Cited in the file of this patent UNITED STATES PATENTS

1. A METHOD FOR THREADING THROUGH A TREATING APPARATUS THE LEADING END OF A SHEET OF WET WEB MATERIAL WITH LOW TENSILE STRENGTH, WHEREIN THE WEB MATERIAL IS TRANSPORTED AIR-BORNE IN AT LEAST ONE RUN BY MEANS OF A TREATING MEDIUM IMPINGED AGAINST THE WEB IN AN UPWARD AND FORWARD DIRECTION, COMPRISING THE STEPS OF PROVIDING A LIGHT-WEIGHT PILOT SHEET OF GREATER TENSILE STRENGTH THAN SAID WEB AND HAVING A SUBSTANTIALLY PLAIN SURFACE OF SUFFICIENT AREA RELATIVE TO WEIGHT AS TO ALSO BE AIR-BORNE AND MOVED FORWARD BY SAID TREATING MEDIUM, PROVIDING ON SAID PILOT A FOLDABLE BAND EXTENDING REARWARDLY FROM ONE SIDE OF SAID PILOT, CONNECTING SAID PILOT TO THE LEADING END OF THE WEB MATERIAL BY FOLDING SAID BAND OVER ONE EDGE OF THE WEB MATERIAL, INSERTING SAID PILOT INTO THE TREATING APPARATUS IN ADVANCE OF THE WEB MATERIAL, AND SUPPORTING AND TRANSPORTING SAID PILOT THROUGH THE DRIER BY THE UPWARDLY AND FORWARDLY DIRECTED COMPONENTS OF THE TREATING MEDIUM TO SUPPORT THE PILOT AND STRETCH THE FORWARD END OF THE SHEET OF WEB MATERIAL IN THE DIRECTION OF TRAVEL THROUGH THE APPARATUS TO PREVENT FLUTTERING AND TEARING OF THE FORWARD END OF THE WET WEB MATERIAL OF LOW TENSILE STRENGTH, THE PILOT AND THE WEB MATERIAL SHEET BEING TRANSPORTED TOGETHER AIR-BORNE BY THE TREATING MEDIUM WITH THE PILOT SHEET ENTRAINING THE FORWARD END OF THE WEB SHEET. 